basically a quantity measuring the correlation (preciser: the dependence structure) of two random variables.

"the corporate CDO world relied almost exclusively on this copula-based correlation model."
"everyone was pinning their hopes on house prices continuing to rise."

the idea, published in 2000, quickly became a metric quants ubiquitously used to evaluate risk and a cornerstone of financial engineering allowing simple modeling of vastly complex risks. particularly default risks of CDO tranches. until august 2007...

the ideas:

tame the nasty nature of real-world dynamical, complex and latent variables by substituting them with a clean and simple number summing up everything

convey an image of what is happening: correlation is more like a constant than a fluctuating variable and all you need to know and compute

let the method be adopted by investors, banks, rating agencies and regulators

Sunday, February 22, 2009

mood: more bewilderment and head-shaking is the human brain big enough to save one of the most intelligent creatures? greenpeace asks cynically in an add, aiming at banning whaling amongst other ocean related concerns.

when i mention i'm vegetarian in restaurants, a frequent response is to point me in the direction of the fish...

greenpeace campaign

fact i: the ocean is humanities last frontier of ignorance

72% of earth's surface covered by sea

97% of the ocean is unexplored

with one yearly NASA budget, the exploration program of NOAA (the National Oceanic and Atmospheric Administration) could be funded for 1600 years

largest mountain range covering 23% of earth's surface area underwater (visited for the 1st time after the moon in 1973)

coral reefs still unexplored between 60 and 150 meters

there are better maps of mars than the 50% of total US territory which lies under the sea

most of the southern hemisphere's underwater terrain is unexplored (more exploration ships in that region during captain cook's times than today)

the seabed is harboring countless well preserved archaeological artifacts

although most of the ocean does not get exposed to photons from the sun, and hence there is no photosynthesis, it is completely erroneous to not expect life

the antarctic sea is, unexpectedly and only recently discovered, teeming with marine life

hydrothermal vent systems are islands of life

bacteria replicating photosynthesis in the dark by chemosynthesis where accidental discovery as no one ever predicted their existence

resilient bacteria living in ph 11 environments

7 new species found per hour of deep reef exploration

2000 to 2500 estimated new species in the indo-pacific ocean alone (vs. 5000-6000 known species)

not only new species are still being discovered, but also new behavior and new ecology

amazing variety of bioluminescent animals

fact iii: the seas are being destroyed at breakneck speed

90% of all big fish have disappeared in the last 100 years

50% of all coral reefs are destroyed

for 1kg of fish ending up in a market, at least 10kg of bycatch was killed and thrown away

1.7% of the blue whale population is remaining

10% of the tuna fish population is remaining

commercial trawlers are forced to access ever deeper seabed due to the depletion of fisheries; this completely destroys potential habitats which are totally unexplored and eradicates possibly unknown species

throwaway plastic accumulating in the sea (half of the 100 billion pounds of plastic pellets a year are made into throwaway plastic produces of which a large fraction ends up in the sea)